A currently popular idea is that many universes exist, each having its own set of physical laws. A 2011 study suggests that even a slight change in the laws of nature means they weren't ‘set in stone' when our Universe was born. The laws of nature we see may depend on our ‘space-time address' – -when and where you happen to live in the Universe.

Analysis of the light from distant quasars from data from the Very Large Telescope (VLT) in Chile to shows that one of the constants of nature appears to be different in different parts of the cosmos, supporting the theory that our solar system is an area of the Universe that is "just right" for life, which negates Einstein's equivalence principle, which states that the laws of physics are the same everywhere.

The change in the constant appears to have an orientation, creating a "preferred direction", or axis, across the cosmos, an idea that was dismissed more than 100 years ago with the creation of Einstein's special theory of relativity.

A 2011 report described how the "magic number" known as the fine-structure constant –- dubbed alpha for short –- appears to vary throughout the Universe, according to a team from the University of New South Wales, Swinburne University of Technology and the University of Cambridge. "This finding was a real surprise to everyone," said John Webb of the University of New South Wales in Sydney, Australia.

“After measuring alpha in around 300 distant galaxies, a consistency emerged: this magic number, which tells us the strength of electromagnetism, is not the same everywhere as it is here on Earth, and seems to vary continuously along a preferred axis through the Universe,” said Webb.

“The implications for our current understanding of science are profound. If the laws of physics turn out to be merely “local by-laws”, it might be that whilst our observable part of the Universe favors the existence of life and human beings, other far more distant regions may exist where different laws preclude the formation of life, at least as we know it.

“If our results are correct, clearly we shall need new physical theories to satisfactorily describe them.”The researchers' conclusions are based on new measurements taken with the Very Large Telescope (VLT) in Chile, along with their previous measurements from the world’s largest optical telescopes at the Keck Observatory, in Hawaii.

The core finding of the study was that the fine structure constant (alpha) determines the strength of interactions between light and matter. A decade ago, Webb used observations from the Keck telescope in Hawaii to analyze the light from distant galaxies called quasars. The data suggested that the value of alpha was very slightly smaller when the quasar light was emitted 12 billion years ago than it appears in laboratories on Earth today.

Webb's colleague Julian King, also of the University of New South Wales, analyzed data from the Very Large Telescope (VLT) in Chile, which looks at a different region of the sky. The VLT data suggests that the value of alpha elsewhere in the Universe is very slightly bigger than on Earth.

The difference in both cases is around a millionth of the value alpha has in our region of space, and suggests that alpha varies in space rather than time. "I'd quietly hoped we'd simply find the same thing that Keck found," King said. "This was a real shock."

King says that after combining the two sets of measurements, the result "struck" them: "The Keck telescopes and the VLT are in different hemispheres; they look in different directions through the Universe. Looking to the north with Keck we see, on average, a smaller alpha in distant galaxies, but when looking south with the VLT we see a larger alpha.

"It varies by only a tiny amount –- about one part in 100,000 -– over most of the observable Universe, but it's possible that much larger variations could occur beyond our observable horizon."

"The fine structure constant, and other fundamental constants, are absolutely central to our current theory of physics. If they really do vary, we'll need a better, deeper theory," said Dr. Michael Murphy, of Swinburne University of Technology.

While a "varying constant" would shake our understanding of the world around us, Dr. Murphy notes: "Extraordinary claims require extraordinary evidence. What we're finding is extraordinary, no doubt about that.

"It's one of the biggest questions of modern science –- are the laws of physics the same everywhere in the Universe and throughout its entire history? We're determined to answer this burning question one way or the other."

The team's analysis of around 300 measurements of alpha in light coming from various points in the sky suggests the variation is not random but structured, like a bar magnet. The Universe seems to have a large alpha on one side and a smaller alpha on the other.

This "dipole" alignment nearly matches that of a stream of galaxies mysteriously moving towards the edge of the Universe. It does not, however, line up with another unexplained dipole, dubbed the axis of evil, in the afterglow of the Big Bang.

Earth sits somewhere in the middle of the extremes for alpha. If correct, the result would explain why alpha seems to have the finely tuned value that allows chemistry – and thus biology – to occur. Grow alpha by 4 per cent, for instance, and the stars would be unable to produce carbon, making our biochemistry impossible.

If the interpretation of the light is correct, it is "a huge deal", agrees Craig Hogan, head of the Fermilab Center for Particle Astrophysics in Batavia, Illinois. But like Cowie, he told New Scientist that he suspects there is an error somewhere in the analysis. "I think the result is not real," he said.

Michael Murphy said that the evidence for changing constants is piling up. "We just report what we find, and no one has been able to explain away these results in a decade of trying," Murphy told New Scientist. "The fundamental constants being constant is an assumption. We're here to test physics, not to assume it."

Webb and colleagues doubled the number of observations and measured the value of alpha in about 300 distant galaxies, all at huge distances from Earth, and over a much wider area of the sky. "The results astonished us," said Webb. "In one direction – from our location in the Universe – alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger."

"The discovery, if confirmed, has profound implications for our understanding of space and time and violates one of the fundamental principles underlying Einstein's General Relativity theory," Dr King added.

"Such violations are actually expected in some more modern ‘Theories of Everything' that try to unify all the known fundamental forces," said Professor Flambaum. "The smooth continuous change in alpha may also imply the Universe is much larger than our observable part of it, possibly infinite."

Professor Webb said these new findings also offer a very natural explanation for a question that puzzled scientists for decades: why do the laws of physics seem to be so finely-tuned for the existence of life?

"The answer may be that other regions of the Universe are not quite so favourable for life as we know it, and that the laws of physics we measure in our part of the Universe are merely ‘local by-laws', in which case it is no particular surprise to find life here," he said.

The X-ray image at the top of the page shows the Large Magellenic Cloud. A dwarf galaxy slowly orbitting, and slowly merging with our own Milkyway. It was named after the Spanish explorer Magellen who discovered it and its companion the Small Magellenic Cloud during his trip around the world in 1519. The LMC is about 170,000 light years from the sun.

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